Touch detectors have been in use to indicate a condition where there is contact between the touch detector and some other solid object (e.g., a finger). Any well-known electromechanical “on/off” switch may be used within a touch detector. Additionally, proximity detectors have also been used to indicate when one object is comparatively close to another object and, further, to measure how far away the object is from the detector.
“Capacitive” sensors may be used in proximity detectors and in touch detectors that require high reliability, as electromechanical switches may break or malfunction over time. A capacitive touch sensor may translate the capacitance of the capacitive sensor into a binary signal, which may be processed to determine whether the measured capacitance exceeds one or more defined capacitance levels. The effective capacitance measured may relate to the distance between the object (e.g., a finger) and a sensor plate. As is known in the art, capacitive sensors may use a) dielectric material (e.g., polycarbonate) to cover the surface of the sensor plate and, therefore, separate the sensor plate and the object.
Unfortunately, medical devices often use input devices that have limited functionality. For example, medical devices may use binary switch assemblies that may require the user to repeatedly perform a task in order to achieve a desired goal. For example, the user may be required to repeatedly depress an “up arrow” switch in order to scroll “upward” through a menu. Alternatively, the user may be required to repeatedly depress a “down arrow” switch in order to scroll “downward” through the menu. The use of such limited functionality controls often make it difficult to use such a medical device.